Why does it takes me so many attempts to logon to

[altecz33]

hi everyone ...i have been experiencing a problem thats has been annoying me for a while now...i have a dell server 2,8ghz 512mb ram and running win2k3 server and i have 5 dell workstations running winxp sp1....the server is a domain sever and it has 2 small directory thats is mapped to my workstations...the prob is every time i try to logon to my server from any machine during either a reboot or a complete shutdown and boot up it takes about 10min or more for the domain server to recognise any of my accounts to let me login it can happen from any one of my workstatons..i removed all the users on the active directory and added them back in but same prob...any solutions thanks